ABSTRACT
Only a very few polymers form truly miscible blends. These include poly(phenylene oxide) (PPO/PS), poly(vinyl chloride) (PVC)-polymeric plasticizers 1]. The rest of the blends, which are either partially miscible or immiscible, may undergo micro-or macrophase . separation,leading to heterophase polymer blends . Thts heterogeneity is an unfavorable one , and this often leads to problems that reflect in the overall performance of the resultant material. Blending can give rise to morphologies that lead to certain specific characteristics. It is expected that this process can give rise to a material with the proper balance of properties than would be obtainable with single polymers. Practically, it is difficult to get the expected combination of properties due to the fact that many of the polymers are thermodynamically immiscible and it is difficult to get a homogeneous product. In an immiscible blend, the situation at the blend interface is critical, i.e., a high-interfacial tension and poor adhesion between the phases are observed. The high
Figure1 Various phase configurations upon the extrusion of binary immiscible blend.
